Most countries place various limitations on the ability of charities to conduct business activities in areas unrelated to their charitable purpose. In this paper, I examine this narrow aspect of the legal framework for charities in the United States and Canada. First, I will briefly provide some background on charities' conduct of such activities. Next, I will broadly outline the current law in each country, highlighting key similarities and differences. Then, drawing on historical evidence, I will try to explain why the relevant law in each country developed as it did. Finally, I will evaluate each country's response, focusing not only on the results of each but also on whether the concerns that led to each were well-founded. Through doing so, I will attempt to draw conclusions as to whether there is a clear winner between the two statutory schemes, and if the experiences of each country can provide guidance for future attempts at reform.